@stan.m The root cause was a thread-safety problem; data was read by the main thread at the same time that it was written by another thread. Specifically, the C++ getter for the QString "value" property was called at the same time that the value was written. Other data was written and read at the same time, but their types write as an atomic operation on the ARM processor. The data that caused the problem was of type: QString.

A QString object's member data is a heap pointer to the 16-bit unicode array. When written and read simultaneously, the C++ getter passes a corrupted pointer into the QML runtime. As I wrote before, the "binding loop" warning came after many of these "first-chance" exceptions and had nothing to do with a true binding loop.

The first-chance exception occurred when two value changes occurred back-to-back and the QML runtime called the C++ getter to retrieve the value at the same time that the second change was written.

My initial "fix" worked because polling the value every 100ms allowed the first change propagate to QML long before the next change comes in.

I since have revised the code to use a mutex to prevent writing and reading simultaneously.

@sierdzio Thanks for your input! The this-object was the parent widget holding the QQuickView. I solved it by saving the root object of the QQuickView:

QObject *obj = quickview->rootObject(); if (obj) obj->setProperty("ticks", tick_count); else qDebug() << "Could not set tick count!";

Anyway, I'll have a look at the different approach you suggest. It sound like a more robust way of interacting with QML.

Best regards, E

ok. Let us look at like this. Instead of web view, put the Rectangle{}
Try to show & hide the rectangle instead of web-view. Till me whether it works or not.
Try something like this
OffLine_Pages.qml

Pane{ id: view property string local_url : "" property string pid : "" property alias vis: web.visible Rectangle{ id : web width: 200;height: 200;color: "red" visible: false } }

@GrecKo said in Binding C++ properties exposed to QML to dynamically created QML objects:

Ultimately I think that you should use imperative object creation only for temporary object needed by the UI layer, like showing a dialog for example. I have yet to see another legit usecase for it (or I don't remember it).

I will keep this in mind!

Hopefully this little discusion might help someone else struggling to understand the same concepts!

@raven-worx: Yes, it's ambiguous because I don't know (or there isn't) a syntax for disambiguating. For example in C++ a roughly equivalent statement, involving a local text and a global text, would be text = ::text which is unambiguous.

Hehe, I was discussing that with others last week, a way to differentiate context properties from regular object properties. Could be used in your case to disambiguate the root context property, or to access model properties from outside a delegate, for example : listView.currentItem::age without having to expose it as a property.
This syntax is not achievable for the moment, but you could do something like this listView.currentItem.Context.property("age"), you won't get notified of any change though. You could also do it for the root context with a singleton exposing it with the same caveat about the changes.

Hi,

Take a look at the MEMBER element of the Q_PROPERTY declaration here.

It likely does what you want.

Hope it helps

@Kofr Hi! If you want to be really sure (because you don't trust the docs or your code ^_^) then add something like qDebug() << "hello"; to the destructor of the model and see how often that's called.

Got it solved :-)

QWebFrame * webGUIframe = qobject_cast<QWebFrame >(sender());
QWebView * webGUI = (QWebView)(webGUIframe->parent())->parent();
webGUI->page()->mainFrame()->addToJavaScriptWindowObject("NativeBridge", this);

@Wilk it's cool! What about JSON serialization?

I will try to use your library in my project http://forum.qt.io/topic/64999/qt-micro-rest-client-framework-beta

@mrjj Thanks)

Hi,

Actually it's a feature that's available within Q_PROPERTY declaration. See here for the MEMBER keyword and how to use it.

Maybe

//main.qml: import QtQuick 2.5 Loader { id: loader source: "MyComponent.qml" onLoaded: { loader.item.property1 = "secret" loader.item.property2 = 777 } } //MyComponent.qml: import QtQuick 2.0 Rectangle { id: rect property string property1 property int property2 TextEdit { id: text_edit anchors.centerIn: parent text: property1 + property2 } }

or

//main.qml: import QtQuick 2.5 Item { id: main width: 200; height: 200 property string property1: "secret" property int property2: 777 Loader { id: loader source: "MyComponent.qml" onLoaded: loader.item.text = property1 + property2 } } //MyComponent.qml: import QtQuick 2.0 Rectangle { id: rect property alias text: text_edit.text TextEdit { id: text_edit anchors.centerIn: parent text: property1 + property2 } }

or

import QtQuick 2.0 Rectangle { id: rect TextEdit { id: text_edit anchors.centerIn: parent // rect.parent -> loader; rect.parent.parent -> Item with id 'main' text: (rect.parent.parent.property1 !== undefined) ? rect.parent.parent.property1 : "" } }

Thank you very much for this nice solution :-)